Machine for coding and decoding messages.



' PATENTED' 001. 17,1905. J. s. BEEMAN.

MACHINE FOR CODING AND DECODING MESSAGES. APPLICATION FILED JUNE 3. 1904v 4 SHEETS-SHBET 1.

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J. S. BBEMAN. MACHINE FOR CODING AND DECODING MESSAGES.

APPLICATION FILED JUNE 3. 1904.

4 SHEETS-SHEET 2.

PATENTED OCT. 17, 1905. J. S. BEEMAN.

MACHINE FOR CODING AND DECODING MESSAGES. APPLICATION FILED JUNE 3. 1904.

4 SHEETS- SHEET 3.

No. 801,964. 1 PATENTED OCT. 17, 1905. J. S. BEEMAN. MACHINE FOR CODING AND DECODING MES-S AGES.

APPLICATION FILED JUNE 3. 1904.

4 SHEETS-SHEBT 4.

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JOSEPH SAMUEL BEEMAN, OF LONDON, ENGLAND.

MACHINE FOR CODING AND DECODING MESSAGES.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed June 3, 1904:. Serial No. 211,067.

To (LZZ 1117mm, if; may concern:

Be it known that I, Josurn SAMUEL BEE- MAN, a subject of the King of England, residing at London, England, have invented certain new and useful Improvements in or Relating to Machines for Coding and Decoding Messages, of which the following is a specification.

This invention relates to machines for coding and decoding messages, its object being the construction of a machine which, although simple to manufacture and in operation, is capable of translating or transposingmessages into or from cipher and can also be readily set to vary the code in many ways, as may be prearranged between the persons using it.

Throughout this specification the signs 2'. 6., the letters of the alphabet, figures, stops, &c., which constitute the actual communication it is desired to transmit-will be designated characters and the signs which are sent by telegraph or otherwise and which form the coded message will be termed symbols.

The risk of the unauthorized translation of a cipher-message greatly decreased if in the same message one character is represented by various symbols. In machines according to this invention this effect is obtained by the use of two or more relatively movable memberssay, for example, two or more disks one having characters marked upon it and the other or others bearing symbols, the number of the characters differing from that of the symbols. For the purpose of this specification, however, it is assumed that only two disks are used. These members are geared positively but unevenly-for example, through gear-wheels having an unequal number of teeth. The difference in the number of the characters and symbols is obtained, say, by adding spaces, signs, numbers, 850., to either or both of them.

When gear-wheels are employed, it is preferred to make the number of teeth on each member equal to or a multiple of the number of characters or symbols marked on that member.

It will be seen that, having due regard for convenience in mechanical construction, the best arrangement is that in which the least common multiple of the numbers representing the gear is as high as possible, for the larger this least common multiple the less frequent will be the repetition of the symbol representing any given character.

To still further increase the difficulty of an unauthorized person decipheringthe message, the machine is preferably constructed so that the order of the characters or the symbols, or both, may be varied. For instance, the member carrying the symbols may be made in two parts, one part bearing some of the symbols and the other carrying the rest. These two parts are movable relatively one to the other, so that the order of the symbols can be readily changed.

It is convenient in practice to use the smaller disk for the characters; but this is not essential, although when the larger disk is used for the characters it is advisable to allow for the fact that when coding the message the smaller disk may sometimes turn through more than one revolution, and hence care must be taken in decoding that the smaller wheel is turned for the same amount. One way of avoiding delay in these circumstances is hereinafter described.

It is to be understood that numerals, signs of punctuation, or any other signs may be placed upon the character-disk and also that any suitable number of parts may be used to make up the character and the symbol disks.

in the accompanying drawings, Figure 1 is a plan of one construction of coding-machine according to this invention. Fig. 2 is a perspective view of the same, parts being broken away for the sake of clearness. Fig. 3 is an elevation. partly in section, on the line 3 3 of Fig. 1, and with parts omitted. Figs. 4, 5, and 6 each show in plan separate disks, which are superimposed when in their working position, as shown in Fig. 1. Fig. 7 is 9. diagrammatic plan showing the relation between the gear and the numbers of characters and symbols.

Like letters indicate like parts throughout the drawings.

i/Vith reference first to Figs. 1, 2, and 3, upon a base-plate A are fixed studs B, carrying toothed wheels O and D, respectively. These toothed wheels C and D gear together, and fixed at the back of the wheel D is a ratchetwheel E, the teeth of which engage with a spring-detent F, having a pin F, which passes through an opening G in a front plate G, screwed onto the base-plate A and inclos ing the cog-wheels.

The cog-wheel O has a large boss 0' and a small boss G which pass through an opening in the plate G, and the cog-wheel Dis furnished with similar bosses D and D which also pass through an opening in the plate Gr ITO made for the purpose. The cog-wheel G carries three disks H, H, and H These are shown separately in Figs. 1, 5, and 6. In their working position they are superimposed, as shown in Fig. 1, and it will be seen that when in this position the projecting teeth on the upper disks H and H fill r practically fill spaces between the letters in the radial spaces near the edge of the lower disk H, so that there is a series of twenty-four letters equally spaced near the edge of the compound disk, I and J, also W and V, being in this instance interchangeable. For the purpose of illustration it is assumed that these letters are used for the characters, and therefore the three superimposed disks form a characterbearing member comprising three portions which are movable relatively to one another when it is required to change the order of the characters. The disks H, H, and H all slip over the smaller boss the lower disk H being provided With a hole H fitting over a pin C fixed in the larger boss C. When adjusted relatively as may berequired for any given code, the threedisks are clamped tightly down onto the boss 0 by means of a nut G which screws onto the boss and is itself kept from being taken right off by means of a screw O, fitting an internal thread in the boss C The cog-wheel D bears two disks H and H which are generally similar to the disks H, H, and H When superimposed, as

shown in Fig. 1, they form a compound symbol carrying member, having a series of twenty-six symbols in equal radial spaces near its edge. The disks H H are clamped in their place by a nut D acting in a Way similar to that described with reference to the nut C and secured by the screw D.

In order that the gear between the character and symbol bearing members shall have the same ratio as that between the numbers of characters and symbols, the toothed wheel C is provided in the example illustrated with thirty-six teeth and the wheel D with thirtynine teeth. This is shown in Fig. 7, which is a diagrammatic plan having the toothed wheels shown in full lines. As the disks carrying the symbols and characters overlap these wheels to some extent, they are not I shown in Fig. 7; but divisions H and'H (shown in dotted lines) indicate the number of characters and symbols, respectively, which the wheels C and D carry.

Fixed to the lower portion of the coverplate G is a bar J, the ends of which, J and J serve as reading-points for the characters and symbols, respectively.

A hinged handle L is provided at one side of the case, so'that the machine can be readily held by some of the fingers of one hand, while the first finger and thumb are used to rotate the character-bearing member.

The operation of this machine is as follow supposing that a message is to be coded: The character-bearing disks H, H,and H and the symbol-bearing disks H H are first set in some prearranged way for example, as shown in Fig. 1. It will be seen that the characters G, B, H arethose immediately to the left of the reading-point J, while the letters S T are immediately to the right of the reading-point J This setting would have been prearranged, and when the disks are secured to their respective cog-wheels the'message is coded by turning the character-bearing member so that each letter of the message comes in turn to the reading-point J. The corresponding symbols which are brought to the reading-point J constitute the transmitted message.

As previously mentioned, it is not necessary that the characters should be smaller in number than the symbols. The converse may be the case; but if so in decoding the symboldisk may sometimes have to be turned through more than one revolution before the proper character appears at the reading-point. To avoid the delay caused by what may be termed a trial-and-error method of decoding under these circumstances, it is convenient to place a mark, such as the arrow-head M, on the case of the instrument in such a position that it indicates for any setting of the machine what would be the character at the reading-point if the member bearing the smaller number of signs were rotated for one revolution. For example, in the machine illustrated the disks H H H carry between them twenty-four signs-that is to say, in the present example, letters-whereas the disks H H bear twentysix, and it being understood that the teeth of the cog-wheels C D are equal in number to or multiples of the letters borne by the respective disks on those wheels it follows that the indicator M must be placed in such a position that it points to the second letter to the left of the one at the reading-point J If now in decoding it is found that the character S does not make sense in the message, the operator knows at once, by looking at the indicator M, that if he rotates his symbol mem ber-namely,the disks HH H for one revolution he Will bring the letter U next to the reading-point J. By this means he can tell if this operation is necessary and can at once proceed with the decoding operation.

Although in the machine illustrated by way of example the characters and symbols consist of letters, it will be understood that in either case the letters may be supplemented by signs of any description, such as marks of punctuation or figures, or that one of the radial spaces maybe left blank. Again, the letters or other signs may be duplicated on the symbol or character bearing member; but in ordinary cases that is not desirable.

Again, it is to be understood that in machines according to this invention the relatively movable members are not necessarily in the form of rotating disks, although such a construction is convenient and preferred.

In cases such as that described, where both the members rotate, they may be geared to gather in any desired way, the essential point being that the gear, whatever it is, shall be positive, such as chain or spur gearing, no slip being possible between the two members.

Obviously a machine according to this invention can, in addition to being used for coding words and sentences, be equally well used for coding code-words, thus insuring secrecy if a code-book has been stolen or fallen into the enemys hands.

hat I claim as my invention, and desire to secure by Letters Patent, is-- 1. In a machine for coding and decoding messages, the combination of relatively movable members bearing respectively unequal Sh 88 numbers of characters and symbols and positive gear between the members the gear having the same ratio as that between the numbers of characters and symbols substantially as set forth.

2. In a machine for coding and decoding messages, the combination of relatively movable members bearing respectively unequal numbers of characters and symbols, positive gear between the members the gear having the same ratio as that between the numbers of characters and symbols and means for varying the sequence of the characters or symbols, substantially as set forth.

3. In a machine for coding and decoding messages, the combination of rotatable members bearing respectively unequal numbers of at t characters and symbols and posltive gear between the members, substantially as set forth.

4. In a machine for coding and decoding messages, the combination of a support or casing, a character-bearing member r0tatably mounted in the casing and comprising a plurality of relatively adjustable disks carrying distributed between them a series of characters, a symbol-bearing member rotatably mounted in the casing and COIIllJI'ISr ing a plurality of relatively adjustable disks carrying distributed between them a series of symbols the number of "symbols being unequal to the number of characters and toothed gear between the character and symbol bearing members the ratio of .the gear being the same as that between the numbers of characters and symbols, substantially as set forth.

5. In a machine for coding and decoding messages, the combination of a support or casing, a character-bearing member rotatably mounted in the casing and comprising a plurality of relatively adjustable disks carrying distributed between them a series of characters, a symbol-bearing member rotata bly mounted in the casing and comprising a plurality of relatively adjustable disks carrying distributed between them a series of symbols the number of symbols being unequal to the number of characters,toothed gear between the character and symbol bearing members the ratio of the gear being the same as that between the numbers of characters and symbols, a ratchet-wheel attached to one of the members, and a springdetent engaging with such wheel, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOSEPH SAMUEL BEEMAN.

itnesses:

HARRY B. BRIDGES, ARcIiD. J. FRENCH. 

